As an exhaust purification device for purifying exhaust gas flowing in an exhaust gas flow passage of an engine, an exhaust purification device described in Patent Literature 1 has heretofore been known. The exhaust purification device described in Patent Literature 1 includes a first casing in which a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) are accommodated, a pipe to which an injection nozzle (injector) for injecting urea water (reducing agent) into exhaust gas is attached, and a second casing in which a selective catalytic reducer (SCR) is accommodated. The pipe is inserted in the first casing so as to extend in a direction substantially orthogonal to the axial direction of the first casing, and is connected to the second casing. The exhaust gas is purified by reducing NOx using ammonia generated by the injection of the urea water.